While hydraulic jacks may be common, many mobile jacks available today are either a single hydraulic cylinder where the hydraulic cylinder must be manually activated or the jack must be activated with an air assist mechanism. Further, most conventional service jack designs use a pantograph style mechanical device to lift the load. Current single cylinder jacks or pantograph designs are not capable of the lifting power needed in some applications. Further the traditional mobile jack designs are difficult to position or are unsafe because they only provide one lifting contact point.
However, the mobile service jack with more lifting power, such as with multiple cylinders, or a jack designed to have more than one lifting point, must still be compact and maneuverable to allow it to easily fit and be placed under a vehicle.
In addition, hydraulic jacks are subject to inadvertent release or failure. With conventional mobile jacks, the operator must place a vehicle lift or jack stand under the vehicle to ensure the safety of the operator in the event of a cylinder failure, once the vehicle is in the lifted position.